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How to read tyre tests?

The same tyre has performs differently at different temperatures and sizes!

A tyre is the third fastest rotating element in a car and the only one that has contact with the road. Is it worth to trust reviews and what should one look for when reading them? How to choose the best tyres?

Tyres should be assessed in terms of steering response, driving safety when cornering, traction and acceleration, noise level, wear, impact on combustion, braking distance in various weather conditions and aquaplaning resistance. What data should drivers search for in tyre reviews? What will distinguish a reliable test from amateur comparisons?

– Independent tire tests are a great opportunity for drivers to find a tyre model that will meet their expectations. The number of tyres available on the market is huge and can be overwhelming when the driver is thinking about buying another set of tyres. Reliable analyses are very helpful and allow drivers to familiarize themselves with the performence of a given model or type of tyre – and, consequently, make a premeditated decision when purchasing them. However, it is worth paying attention to the key assumptions adopted in the tests – only then can we make a wise, conscious choice –says Piotr Sarnecki, general director of the Polish Tyre Industry Association (PTIA).

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When reading test, let's not just base our judgement on the length of bars on the charts, because the scale adopted in them, for example in the case of braking distances, can be misleading. Therefore, let's compare and pay special attention to the figures. – For example, in a braking distance graph, the difference between the bars may be small, because such is the scale adopted. However, in numerical data presented it will be, for example, 4 meters, which is almost the entire length of a medium-size car – adds Piotr Sarnecki.

A reliable tyre test will always contain information on:

1. The air temperature at which the test was performed

It has a huge impact on test results – reviews which do not inform the reader of this value are of little use to the drivers, who are looking for reliable information. For example, a test of winter tyres on a wet or dry road at 15-20°C will always show a lot worse results when compared to summer tyres. If the test were done at temperatures below 7-10°C, we would see that the soft rubber compound of winter tyres makes a significant difference when it gets cold. The temperature and differences in weather conditions in the spring-summer and autumn-winter seasons have such a significant impact on the performance of these types of tyres – and especially on the length of the braking distance and the safety and drivers – that each test should state this variable. This particularly applies to the comparison of all-season tyres with seasonal tires.

2. The size of the tyre

It is not enough just to name the manufacturer of the tyre and its model – let’s look for information on the exact size of the tyre that was used in the tests. The same model can have different performance depending on the size of tyre! Highly rated tyre model in one size may have worse results in a tyre test of a different size.

3. Tyre test surface

Information on the type of surface on which the test was performed is, fortunately, often included in test of the performance of tires. Independent tire tests are usually performed on several different surfaces – dry, wet, and for winter or all-season tires, also on snow-covered or, less often, ice-covered road, so as to compare their performance in a wide range of climatic and road conditions. The surface type has a huge impact on the test results in all its criteria.

– Keep in mind that purchasing good, brand new tires is the easiest way to increase your safety on the road. When driving on used tires, we risk the lives of our relatives, all road users and ours – addsPiotr Sarnecki.

Read the label

Before we read the detailed tests, we can easily narrow down the search for tyres by comparing labels. A glance at the basic parameters of the tyres will allow one to quickly familiarise themselves with the tyre market. From November 2012, tyres sold in countries belonging to the European Union must come with appropriate labels. They make it easier to compare the three basic tire parameters before making a purchase:

Fuel efficiency (dispenser icon) – determined by the coefficient of rolling resistance of the tyre. It is expressed in classes A to G, where A is the most economical tyre. The highest A class tyres will save you up to 7.5 percent of fuel, as compared to the lowest G class tyres.

Wet grip (rain icon) – informs you of the braking distance of the car on the wet surface. Class A means that the tyre model has the shortest braking distance – at a speed of 80 km/h your braking distance will be even 18 m shorter than with the lowest G class tyres.

External rolling noise (loudspeaker icon) – the value emitted by a given tyre, when driving at a speed of 80 km/h, expressed in decibels. The scale of noise has the form of three beams - the more beams are black, the louder the car is.

Such information must also be provided in e-shops or on bills confirming the purchase. Of course, these are not the only important parameters – the braking distance on dry surfaces or snow, resistance to aquaplaning, cornering and traction are also of great significance and those are compared in independent tests published in press and on the Internet.